Flat tax would simply replace existing tax tables and all of the special interest deductions would disappear [well, almost all].

Fair tax would require the repeal of the entire income tax code... noble, but difficult.  If this did not happen, we could end up with a VAT and an income tax when Obama II is elected sometime in the future.

Online residency verification will never make it through the courts... discriminates against the poor and stupid... Rev. Jackson will be the most vocal opponent.

And everyone getting the same "prebate"... well, that's not fair that the rich people making $100,000 should get some of the poor people's money... Rev. Jackson will be the most vocal opponent.

It is the same progressive structure as my example of a flat tax with the same dollar value exemption.  The effective tax rate of X% is reduced by returning constant $Y against a variable amount paid.  That's the same result as variable tax rates.  Put it on a spreadsheet and see for yourself.